Non-Terrestrial Network Timing Advance for Doppler Synchronization
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Solution Overview
Problem
Satellite communication systems face challenges with synchronization due to high velocities and Doppler effects, leading to issues with signal-to-noise ratio and high latencies, which affect the performance of transmission control protocol (TCP) services.
Innovation Solution
A wireless transmit and receive unit (WTRU) receives system information from a base station attached to an airborne or spaceborne vehicle, determines a timing offset based on location information, and transmits a preamble using the PRACH resource, receiving a random access response (RAR) with a timing advance (TA) command to adjust uplink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite communication systems use traditional terrestrial timing advance methods, then the system can maintain basic synchronization, but the high velocities and Doppler effects cause signal-to-noise ratio degradation and increased latency
Solution Approach 1:
The system performs preliminary timing offset determination based on location information before actual communication occurs. The WTRU calculates the timing offset using its known location and the satellite's orbital parameters in advance, allowing it to pre-compensate for propagation delays and Doppler effects before transmitting signals, thereby reducing overall latency while maintaining synchronization
Solution Approach 2:
The timing offset is made dynamic rather than static. The system continuously updates the timing offset based on real-time location information and satellite motion parameters. This dynamic adjustment allows the system to adapt to changing Doppler effects and propagation delays as the satellite moves, maintaining synchronization reliability while minimizing latency through optimal timing adjustments
2Reliability
If satellite communication systems use traditional timing advance methods, then the system can maintain basic synchronization, but signal-to-noise ratio deteriorates due to high velocities and Doppler effects
Solution Approach 1:
The system performs preliminary timing offset determination based on location information before actual communication occurs. The WTRU calculates the timing offset using its known location and the satellite's orbital parameters in advance, allowing it to pre-compensate for propagation delays and Doppler effects before transmitting signals, thereby reducing overall latency while maintaining synchronization
Solution Approach 2:
The timing offset is made dynamic rather than static. The system continuously updates the timing offset based on real-time location information and satellite motion parameters. This dynamic adjustment allows the system to adapt to changing Doppler effects and propagation delays as the satellite moves, maintaining synchronization reliability while minimizing latency through optimal timing adjustments
3Reliability
If the WTRU uses location information to determine timing offset, then synchronization is improved, but the device complexity increases due to additional calculations and information processing
Solution Approach 1:
The WTRU performs autonomous timing offset determination using its own location information and publicly available satellite orbital parameters. The device independently calculates the timing offset without requiring complex network-assisted synchronization protocols or additional infrastructure, thereby improving synchronization while keeping the solution self-contained and relatively simple to implement
Solution Approach 2:
The location information serving mechanism is designed to be universal, using the same location data that the WTRU already possesses for other purposes (such as positioning and navigation). This multi-functional use of location information avoids duplicating measurement systems and reduces overall device complexity while still enabling accurate timing offset determination
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves synchronization in satellite communication systems by reducing latency and enhancing signal quality, enabling more efficient data transmission and supporting a larger number of users with improved modulation-coding schemes.
Implementation Method 1
timing offset based on a plurality of information, such as the location information and the system information
Implementation Method 2
satellite communication systems face challenges with synchronization due to high velocities and Doppler effects
Data Source
AI summary
Methods, systems, and devices for addressing timing advance (TA) in non-terrestrial network communication is disclosed herein. A wireless transmit and receive unit (WTRU) may receive system information from a base station attached to an airborne or spaceborne vehicle that indicates a physical random access channel (PRACH) resource. The WTRU may determine a timing offset based on a plurality of information, such as the location information and the system information. The WTRU may transmit a preamble using the timing offset via the PRACH resource. The base station may receive the preamble and send a random access response (RAR) that includes, for example, a TA command. The WTRU may receive the RAR including the TA command and combine the timing offset with the TA command to determine an actual TA, after which the WTRU may use the actual TA for uplink transmissions.